A fail-safe brake on vehicles on the type concerned is understood to mean a brake system intended in the event of a fault in the normal vehicle brake or "road brake" to reduce the speed of the vehicle or to stop it altogether. For this purpose, the fail-safe brake system should have an operating means completely separated from the road brake and the operating means should be easy for the driver to reach and operate. Further requirements on the fail-safe brake system are that it must be operationally reliable and that the risk of faults occurring in the fail-safe brake system is virtually eliminated.